1. Field of the Invention
This invention relates to an electrostatic printer of the type that employs an array of styli to impress a dot-like pattern of electric charge on a recording medium such as a sheet of paper. Toner is subsequently applied to the recording medium to provide a visible image of the charge pattern. The invention relates to improved control of the size and shape of the dots impressed on the recording medium by the styli.
In printers of the type to which the invention relates a sheet of paper is passed beneath an array of electrically conducting styli. The styli are individually energized with high voltage pulses, thereby leaving dots of electric charge on the paper, the dots being applied in a pattern corresponding to the image to be recorded. In printers of this type it is desirable that the dots be well defined so that one can record a faithful reproduction of a desired image. Unfortunately, these printers have heretofore been characterized by dots which are not sufficiently controlled, either as to size or to shape, thereby undesirably degrading the recorded image.